Rust inhibiting composition



Patented Dec. 30, 1952 RUSTINHIBITING COMPOSITION Alfred B. Matnsaak, Jersey City, N. 1., assignor to.

Standard Oil Development company, a corporation of Delaware No Application May 22, 1948,

- a Serial No. 28,760

team. (01. zen-m)- 1 Thisinvention relates .to rustpreventing oil compositions and more particularly to mineral lubricating oil compositions which tend to inhibit rusting and corrosion of metal parts which are exposed to moisture. V

A primary object of the present invention is the preparation of compositions which may be employed as internal combustion engine lubricants and which will also serve for the protection of exposed surfaces of such engines when the same are not in use. When operating engines in climates having a high humidity, rusting begins within a very short period of time after the engine is shut down. The compositions of the present invention are particularly valuable in preventing such rusting, and they are valuable not only in the lubrication of internal combustion engines, but with oil bases of suitable viscosity they may be employed as turbine oils or as lubricants for fire arms, ordnance equipment, industrial machinery, etc., and with more volatile oil bases and in combination with fatty substances they may beapplied to form protective coatings for'metal surfaces which are exposed to humid air.

The corrosion preventing compositions of the present invention are formed by adding to a suitable oil base an additive consisting of a mixed carboxylic acid-sulfonic acid ester of a polyhydroxy alcohol, where the carboxylate portion of the esteris derived from an aliphatic or cycloaliphatic carboxylic acid having from 1 to carbon atoms per molecule, and the-sulionate portion is derived from an alkane or cycloalkane sul- 'fonic acid having 1 to 30 carbon atoms per molecul'e. Such a mixed ester is formed by esterifying at least one hydroxyl group of polyhydroxy 7 alcohol with a carboxylic acid and at least one hydroxyl 'group with a sulfonic acid.

Where the polyhydroxy alcohol is a diol the resulting 'diester, in order to come within the can be conveniently handled in the subsequent esteriiication with a sulfonic acid. In this process a small amount of diester may be formed by completely esterlfying the diol with either the carboxylic acid or the sulionic acid, but such bystearic,

than two hydroxyl groups the polyhydroxy alcohol may be partially or completely 'esterifled. The resulting ester must contain at least one carboxylic acid radical and at least one sulfonic acid radical, and dicarboxylic acids may be employed instead of mono-carboxylic acids.- In the latter case dicarboxylic acids containing 0 to 8 carbon atoms in the chain between the two carboxyl groups are preferred. In the preparation of these polyesters one or more than one carboxylic acid and one or more than one sulfonic acid may be employed. Where a polybasic carboxylic acid is employed either normal esteriflcation or cross linkage esteriflcation may occur, but

in either case a satisfactory mixed ester will be formed.

In the preparation of the mixed esters of the present invention any alcohol may be employed containing at least two hydroxyl groups, where the hydrocarbon portion of the alcohol is an alkyl or cycloalkyl group. Such alcoholsmay contain an inert substituent in the molecule. A preferred group of alcohols comprises those containing four hydroxyl groups per molecule, among which pentaerythritol and sorbitan are especially suitable examples. As furtherillustrations of alcohols which may be conveniently employed in accordance with the present invention may be mentioned ethylene glycol, propylene glycol, 1,3-propanediol, glycerol, pentaglycerol, tris(hydroxymethyl)nitromethane, 2-m ethyl-2- nitro 1,3 propanediol, 2-ethyl-2-nltro-1,3-propanediol, sorbitol and inositol.

The carboxylic acids which are suitable for the I preparation of the rust inhibiting compositions of the present invention include any aliphatic or cycloaliphatic carboxylic acids having l-to 30 carbon atoms per molecule and these include saturated as well as unsaturated acids having one or two carboxyl groups. Among the more preferred examples oi such acids may be meni tioned acetic, butyric, valeric, lauric, palm-itie. oleic, linoleic, ricinoleic, eleomargic,

erucic, behenic, arachidic, lignoceric and similar fatty acids, also dicarboxylic acids, such as oxalic acid, succinic acid, maleic acid and fumaric acid,

- as'thls generally produces a liquid product which products will be formed only in small quantities and will not appreciably eflect 'the inhibiting properties of the primary product. Instead of employing a carboxylic acid or sulfonic acid as such, the anhydride or acid halide of the desired acid in each case may be employed in known esteriflcation processes.

the polyhydroxy alcohol contains more also the naphthenic acids, as well as carboxylic acids derived by the oxidation of petroleum prod-. ucts. Naturally occurring products containing any of the above or similar acids, such as tall oil, castor oil, soybean oil, linseed oil, olive oil, tung oil, rapeseed oil, menhaden oil and the like, or acids derived therefrom may be conveniently employed. The sulfonic acids which are to be employed in the preparation of the mixed esters include any sulionic acid derived from a saturated aliphatic or cycloaliphatic hydrocarbon containing 1 to 30 carbon atoms per molecule. These may include pure acids, such as ethanesulfonic acid, as well as mixtures of sulionic acids such as a those obtainedinthe sulfonation of petroleum oils or the oxidation of mercaptans.

Some specific examples of mixed esters derived from the alcohols and acids described above are pentaerythritol mono-oleate mono-ethanesulfonate, pentaerythritol di-oleate mono-petroleum-sulfonate mono-ethanesulionate. pentaerythritol mono-laurate tri-ethanesulfonate. pentaerythritol mono-petroleum-sulfonate monoacetate, pentaerythritol mono-maleate monop'etroleum-suli'onate mono-oleata sorbitan monooleate mono-ethanesuli'onate. sorbitan di-stearate di-petroleum-sulfonate, sorbitan mononaphthenate mono-oleate mono-ethanesulionate, glycerol mono oleate mono ethanesulfonate.

glycerol mono-palmitate di-petroleum-sulfonate,-

glycerol mono-cleats mono-acetate mono-petroleum-sulfonate, ethylene glycol mono-cleats mono-ethanesulfonate, and homologg thereof.

The additives of the present invention may be advantageously employed with petroleum fractions of a wide variety, although their preferred use is in lubricating oil bases to form lubricant compositions which also act as corromon preventives. The base stocks may be derived from various types of crude petroleum and may consist of dlstillates or blends of various kinds which have been refined by any of the conventional methods. Synthetic oils may also be used such as those obtained by the polymerization of olefins or by the hydrogenation of coal or its products. In the case of lubricants, the base stock chosen will normally be that oil which without the new additives gives the optimum performance in the service contemplated. These base oils may vary considerably in viscosity and other properties depending upon the particular uses for which they are desired. For crankcase use they usually range from about 40 to 130 seconds viscosity.Saybolt at 210 F. The viscosity index may range from less than 0 to 100 or even higher. Turbine oils usually have a viscosity of 40 to 60 seconds Saybolt at 210 F. Corrosion preventing compositions other than lubricating oils may comprise base stocks of a wide variety with respect to viscosity and may consist of mixtures of base stools, as in slushing oils, which may consist of a mixture oi. naphtha and lubricating oil and may contain small amounts of petroleum or a fatty compound such as degras.

.In addition to the materials to be added to the base stock according to the present invention,

other agents may be present in lubricating com-- positions and other corrosion preventing compositions, such as heat thickened fatty oils, Sill-'- were' obtained:

l'onnd Olmsted Baponiflutbn No KOH/g. 21a s 227. a Acidity do 4. 4s 0 Sulfur peroent .v 4. ll 0. 50 Carborn do. 08. 17 01. 00

40 Hydrogen "do.-. 10. 77 9. 82

furized oils, organo metallic compounds, metallic or other soaps, sludge dispersers, antioxidants, thickeners, viscosity index improvers, pour point depressors, cilinessagents, resins, olefin polymers and colloidal solids such as graphite or zinc oxides. Typical addition agents serving the.

' 0.01% to 10% by weight and in some cases larger proportions may be employed to advantage.

The following. examples illustrate the application of the present invention to a lubricant-suitscope of the invention in any way.

EXAMPLE 1 To zoos 5. (it mol) of pentaerythritol monooleate (prepared by esterifying equal molecular quantities of pentaerythritol and oieic acid) in.

a 1-liter 4-necked flask equipped with a stirrer, thermometer, separatory funnel, nitrogen inlet tube, and reflux condenser equipped with a water separator was added 250 g. of toluene. The solution was refluxed at 120 .C. for 55 hour to remove a small amount otJ/ater (0.2 cc.) from the reagents. Additional refluxing produced no more water. To the refluxing-solution 84.3 g. (0.58 mol) oi ethanesultonic acid was added dropwise over a period of 1 hour with the temperature of the solution at 116" 0. Water was produced immediately on adding the ethanesulfonic acid. After refluxing for 3 hours 9 cc. of watery distillate (about ,5 mol of water) had separated from the refluxing liquid. The material was then cooled and washed twice with a saturated aqueous sodium bicarbonate solution. when the second bicarbonate washing evolved no more carbon dioxide, the ester solution was washed with water to give a solution neutral to litmus paper. The toluene was removed by distillation under reduced pressure. The ester product was a dark amber colored viscous material weighing 220 grams. The following inspections inhibiting properties by employing it in a-1% concentration by weight in a phenol treated Mid-Continent oil of 120 seconds viscosity Saybolt at 210 F. as a crankcase oil in a single cylinder air-cooled aviation type engine of '5.7 H. P., manufactured by the Wisconsin Motor Corporation. The engine was operated at a speed of 2400 R. P. M. on 91 grade aviation gasoline containing 4 cc. tetraethyl lead per gallon. After running the engine for 8 hours with this test oil, the stainless steel cylinder, which had the same composition as the cylinders of a full scale airplane engine such as a Pratt and Whitney R1340 engine, was removed from the engine and stored in a Tenney humidity cabinet in which the temperature was caused to vary between 72 and F. and the relative humidity between 94% and 53% during each 24-hour period. Typical conditions in a tropical climate were thus simulated. After each 24-hour cycle the amount of rust present on the cylinder wall was observed and the storage period continued until a test period of 10 days had been completed; The amount of rust present at each observation was recorded as the percent of the total cylinder barrel area which had become' rusted. A rating of 0.5% denotes a rusted area covering approximately V sq. in., since the total 6 cylinder barrel area is about 56 sq. in. For comparative purposes the base oil with no inhibitor J 2 was evaluated to determine its rust producing To 133.5 g. (Y mol) of pentaerythritolmonoproperties in a similar manner. The observaoleate in a 1-liter 4-necked flask equipped with 'tions made in the two'tests are given in the 01- 5 a stirrer, thermometer, separatory funnel. ni

lowing table: trogen inlet tube, and reflux condenser was added mol) of ethanesulfonic acid was-added drop- Culinder rusting test (percent of cylinder wall rusted) Days of Storage For comparison, it may be noted that other tests 100 g. of toluene. To this mixture cooled. to 3 have shown that pentaerythritol mono-oleate C. was slowly added 42.9 g. W; mol) of ethanesulwithout the ethanesuli'onate radical permitted fonyl chloride over a period of hour. Stirring rusting to an extent of about 10%of the cylinwas continued for 2' hours, after which 52.5 g. der after 5 days storage under the conditions of mol) of pyridine was added over a period of the test. 1 hour (to absorb the HCl lay-product), the

EXAMPLEZ temperature being maintained at 3 C, After tirring for 3 more hours the mixture was al- To 214.5 g. (as mol) of sorbitan mono-oleate s (prepared by esterifying equal molecular proporzfg s room temperature- The tions of either sorbitan or sorbitol with oleic W h g g oride was filtered 03 and acid) in the same apparatus as that used in gi' i i' gg g s i fi fggg Example 1 was added The washed with dilute hydrochloric acid, aqueous tion was then refluxed at 118- C. for 1 hour dursodium .bicarbonate solution, and water, after ing which time about 0.5 cc. of watery distillate which the toluene was pp OK at 30 mm.

no was collected Additional refluxing produced named pressure. The product weighing 153 g.

l water To the refluxing soutlon 55 1 g (representing a yield of 93.2% based on the pentaerythritol mono-oleate) was a dark amber wise over a period of 2% hours. Water was produced immediately. After 3 hours refluxing ggz gg having the following 1 8.6 cc. of water distillate (about mol) had collected in the water separator. The solution was diluted with 400 g. of toluene, washed with a saturated": aqueous sodium bicarbonate solution d Calculated and then finally washed with water until neutrial to litmus paper. The toluene was distilled igygggie gg-gggg 5 223.3 oil under'reduced pressure to give a dark amber Sulfur 1 a w colored ester product weighing 203 g., which 3 33g represented a yield of 78%. 1

This product wasevaluated in the same manner as that described under Example 1, with the following observations of the condition of the This product was evaluated in the manner d cylinder after storing for various periods in scribed under Example 1. with the following obhe humidity i servations oi the condition of the cylinder after Cylinder rusting test (percent of cylinder wall rusted) Days of Storage Uninhlbited Di] 6 10 15 22 30 35 39 42 44 45 Same-{4% Ester 1-5 2 3 5 5 5 5 5 6 7 For comparison, it may be noted that with a blend storing for various periods in the humidity cabicontaining 1% sorbitan mono-oleate 14% rusting net:

Cylinder rusting test (percent of cylinder wall rusted) DaysoiBtoi-age izass oraeio Uninhibited oii.... I Same-{4% Ester 3 3 Tm: a? 0 2' a 41 2 0% a: g

was observed at the end of 5 days under the It will be recalled that tests have shown that same test conditions. Y I '76 pentaerythritol mono-cleats without the ethancsulionate radical permitted rusting to an extent of about 10% 01' the cylinder after 5 days storage under the conditions oi the test.

From the results of the three examples de scribed above, it will be seen that the addition of the ethanesuli'onate group to the pentaerythritol mono-oleate and the sorbitan monooleate group markedly increased the rust inhibiting properties of the compound. The invention is not to be considered as limited by any of the examples described or disclosed herein, which are given by way of illustration only, but is to be limited solely by the terms oi the appended claims.

What is claimed is: p 1. As a new composition of matter a mixed partial ester of a polyhydroxyl alcohol selected from the group which consists of sorbitan and pentaerythritol, the esteriiying group being oleic acid and ethane sulfonate.

polyhydroxyl alcohol selected'from the groupwhich consists of sorbitan and pentaerythritol with a sufllcient amount of oleic acid to esteriiy one, hydroxyl group of said alcohol, and subsequently reacting the product thus formed, with a sufllcient-amount of an acidic material selected from the group which consists of ethane sulionic acid and ethane sulfonyl chloride to esterify an additional hydroxyl group of said aleohol.

4. The method which comprises reacting ALFRED H. MATUSZAK.

REFERENCES crran The following references are ot record in the file of this patent:

. UNITED STATES PATENTS Number Name Date 2,023,388 Harris Dec. 3, 1935 2,212,521 Ha'rris Aug. 27, 1940 2,231,228 Singer Feb. 11, 1941 2,285,773 Harris June 9, 1942 2,371,284 Cook et a1. Man 13, 1945 2,433,646 Carter at al. Dec. 30, 1947 2,460,968

Bert Feb. 8, 1949 

1. AS A NEW COMPOSITION OF MATTER A MIXED PARTIAL ESTER OF A POLYHYDROXYL ALCOHOL SELECTED FROM THE GROUP WHICH CONSISTS OF SORBITAN AND PENTAERYTHRITOL, THE ESTERIFYING GROUP BEING OLEIC ACID AND ETHANE SULFONATE. 